Let me see if I can be a little more detailed about my build process for everyone. This is the bk for the herms system that I am completing. I am not that familiar with the automation aspect of these systems, and did not have the money yet to get started, so I kept this as simple as possible.
The beginning, is obviously just a simple keggle, with a ball valve, sightglass, thermometer and diptube. I went all weldless fittings from bargainfittings.com, as I did not have access to a welder.
After I did this, the other addition is a herms coil. This is currently 10 feet of ½ inch copper coil inside the keg, but I will be adding another 10 feet using some compression fittings to expand the length. The fittings on the inside of the tank are simple 90 degree compression fittings from the lhs. The top of the coil is the “in”, and is made of a weldless bulkhead and quick-disconnect(from mcmaster). The bottom of the coil is the “out” and is another bulkhead, and stainless valve and another quick-disconnect. I have used this for the immersion chiller, and running pretty cold tapwater on the 10 foot coil it isn’t great, but it does cool 11 gallons from 200 down to 80 in about 50 minutes. This is the first reason that I will expand the coil. When I finish this system, this coil will be used to control the temperature in the mash tun by circulation wort through the coil. Since it is not automated, I will have to keep a close eye on the temps of both kegs, as I mash and circulate.
This second modification is actually pretty simple. There are two 2000w elements mounted into the keggle. I put them on opposite sides of the keg, and installed one about an inch above the other, as I had read posts about resonance between the two elements if they are to close. I got these from amazon, as the lhs didn’t actually carry the 2000w elements. I believe that I paid about $20 for both delivered.
The hole for the elements is a little larger, I got the step bit off of bargainfittings.com. The larger of the two bits they sell is the one you need for these 1 3/8” holes. This bit will also drill the smaller holes for the other bulkheads, if you only want to get one bit. The elements actually come with a rubber oring to help seal, but you need a locknut, and I also got a washer. These were found in the lhs in the electrical area, as they are the right size to screw into the element. I installed it the same as the bulkheads from bf.com, and once I used thread tape, there were no leaks.
The back of the element has two posts for the wiring. I got about 6 feet of 18 gauge wire that is waterproof, and attached them to the element. The next step is to get some pvc fittings that barely slide over the back of the element. I believe that I got a 1 ½” coupler that is threaded on one end, as well as a threaded plug. The plug gets drilled so that the wire can barely slide through. Put the coupler on first, then the plug, screw it in, and slide it so that it covers the back of the element. I used jb weld to seal the coupler to the back of the element. Hot glue doesn’t work .
I mounted a metal switch box to the base of the keg, and ran the wires from the element to the switch. A three foot or more cord is also needed. The wiring is simple. Wire nut the black to the black. Screw one of the white wires to one side of the switch, and the other to the other. Your switch now stands in between the hot wire to the element. Attach the ground, insert the switch and put on the cover, and you are good to go. I also cut some scrap plexiglass and mounted to the top of the box as a splash guard, as the box I got wasn’t waterproof, although that would be the safe way to go.
Here is an approximate parts and price list
Keg 25(craigslist)
Bargainfittings parts 131.50(with bit)
Mcmaster disconnects 40
Misc plumbing 40
Elements 20
Switches/box/etc 35
Approx total 291.5
